1. Field of the Invention
The present invention relates to a retractable closure system that employs a flexible, top-hung, upwardly retractable, downwardly extensible, curtain-like closure which is formed from a combination of tear-resistant fabric and torsion spring material having a "retracted form memory" that normally causes the closure to coil during retraction to form a roll when retracted, and that utilizes the action of a power operated means and the influence of gravity to overcome the action of the spring material to cause the closure to extend by being "unrolled," with the power operated means preferably taking the form of a spaced array of fabric connected, vertically extending, fluid-pressure-expansible members that inflate when pressurized to extend the closure, and that deflate when depressurized to permit the closure to retract and roll-up under the influence of the torsion spring material. In preferred practice, the torsion spring material and the pressure expansible members extend along and connect with only an upper portion of the tear-resistant fabric--an arrangement that causes closure "roll-up" during retraction to be initiated near the juncture of upper and lower portions of the curtain-like closure so that the lower portion of the curtain-like closure is caused to be coiled into a "double roll" together with the upper portion, with this form of closure being particularly well suited for use in selectively opening and closing side walls of a freight hauling vehicle such as a semi-trailer. An optional vehicle-connected tensioning and latching system is disclosed for releasably retaining the closure in its "extended" or "closed" position. Improved components for mounting and connecting closure components also are disclosed.
2. Prior Art
The use of flexible closures such as tarpaulins to close, cover, curtain or partition selected areas typically has associated therewith a number of drawbacks. Among these shortcomings are difficulties that tend to be encountered 1) in drawing flexible closures into proper "extended" or "closed" positions, 2) in securing flexible closures once they have been properly extended or closed, 3) in establishing suitable weather resistant seals about the perimeters of properly extended or closed closures, 4) in retracting flexible closures when they are to be retracted or withdrawn from their extended or closed positions, and 5) in protectively storing flexible closures after they have been retracted or withdrawn from their extended or closed positions.
The relatively heavy, bulky and very flexible nature of large tarpaulins often cause such closures to be quite difficult to draw into properly extended or closed positions for service as closures, covers, curtains and partitions. Areas across which tarpaulins are to be stretched often are defined by tall or otherwise relatively inaccessible framework that prevents ready access. Wind, rain and other environmental factors such as the presence of snow and ice often contribute to the difficulty that is encountered in moving tarpaulins into position. The size, shape and other characteristics of a structure that is to be covered also may significantly complicate the effort that must be expended to draw a tarpaulin into a proper operating position, especially if the structure that is to be covered has pointed projections or other formations that may tend to cut, impale or otherwise hinder the damage-free positioning of areas of a tarpaulin that contact such formations.
Releasably securing a tarpaulin in its extended or closed position typically calls for the use of a relatively large number of ropes or straps that individually must be drawn taut and tied in place. The investment of time and effort that typically must be expended to properly secure a tarpaulin to prevent its being drawn out of proper position and/or damaged by wind, rain or other environmental conditions often proves to be unwieldly.
If weather-tight seals need to be established about any significant portion of the perimeter of a tarpaulin, prior proposals typically call for the relatively clumsy use of tape or other disposable means for establishing make-shift "seals" that seldom are capable of serving more than a single use. The need to repeatedly check the integrity of and to repeatedly repair clumsily formed, make-shift seals that extend perimetrically about portions of tarpaulins represents quite an unsatisfactory characteristic that has come to be associated with present-day use of tarpaulins as flexible covers.
Because tarpaulins in present day use tend to be "retracted" by substantially the same sort of primitive "pulling and tugging" technique that typically is used to effect movement into an extended or closed position, the business of removing or withdrawing tarpaulins from their operating positions tends to be characterized by substantially the same types of drawbacks that are associated with moving tarpaulins into their operating positions. Moreover, damage to tarpaulins that is occasioned during removal from service often exceeds damage that is incurred during installation both because "removed" covers tend to be jerked and tossed about with somewhat less care than characterizes the handling of such covers while they are being "installed," and because removed covers often are "dropped" with abandon once they have been pulled free from the structures on which they have been supported during use.
Storing a flexible cover such as a tarpaulin when it is not in use typically has been attended to in one of two ways: 1) by folding the tarpaulin and removing it to a storage location where it usually is protectively housed to prevent its being exposed to the elements; or 2) by gathering portions of the tarpaulin to form some manner of roll or bundle of closure material that is lashed together or otherwise secured so it can be held in place at a location that is relatively near where the tarpaulin next will be put into service. Folding or bundling a flexible closure such as a tarpaulin requires an undesirable investment of time and effort, and easily can cause significant wear and tear unless a special effort is made to protect the integrity of the tarpaulin during the exercise. If protective storage enclosures are to be provided to properly shield folded or bundled tarpaulins from the effects of weather and the like, the cost of providing such enclosures, and of providing upkeep adds to the cost that is associated with the use of tarpaulins.
Over-the-road freight hauling vehicles such as flat bed trucks and trailers provide particularly demanding environments wherein flexible covers and closures such as tarpaulins are used to retractably cover and close top, side and rear wall openings through which loading and unloading access periodically must be provided. In recognition of drawbacks (such as are described above) that typically are encountered when tarpaulins are to be used to selectively cover top, side and rear wall openings of freight hauling vehicles, a variety of proposals have been made in an effort to provide so-called "curtainside vehicles" with permanently attached, movably mounted flexible closures that can be retracted and extended between "retracted" and "extended" operating positions.
A number of proposals for "curtainside vehicles" call for the use of manually movable, track-mounted closures with accordion-fold walls. Closure supports that are utilized in implementing these proposals tend to be either 1) relatively primitive and difficult to operate, or 2) unduly complex, expensive and subject to breakdown.
Other proposals call for "curtainside vehicles" to employ spindle-mounted sheets of tarpaulin-like flexible closure material that are "rolled" and "unrolled" to move the sheets between storage and operating positions. Electric motors, electrical controls and interconnecting circuitry typically are provided to operate the rolls to effect retraction and extension of the closure material, together with a number of relatively movable drive components--all of which adds undesirable weight and complexity, and tends to unduly encumber the vehicles on which such components are carried.
To render so-called "curtainside vehicles" easier to load and unload, various types of removable wall components have been proposed for use in the framework of side and top walls. Component removability is desired so that side and top walls can be "opened" sufficiently to permit vehicle loading and unloading to take place in a substantially obstruction-free manner. Complicating the need to provide removable side and top wall components is a competing need that must be addressed concurrently, namely the need to retain in place a sufficient number of side and top wall components to ensure that the retracted closure members continue to be properly supported. Providing an ideal type of support system that not only includes a relatively large number of removable components but also serves to adequately support retracted closures presents a challenge that has not been adequately addressed by prior proposals. Also inadequately addressed by prior proposals is the need that often arises for removable component wall structures to serve as so-called "load bearing walls"--wall structures that will withstand being engaged and impacted by shifting cargo and the like.
3. The Referenced Parent Case
While the above-referenced Parent Case addresses many of the needs and shortcomings delineated above, the present application builds upon the subject matter of the Parent Case and presents to a number of improvement features, many of which can be employed not only on new curtain-like closure embodiments that are disclosed in the present document, but also on curtain-like closure embodiments of the type that are disclosed in the Parent Case.
While the Parent Case discloses closure features that are applicable to a curtain-like closures of a variety of types and/or that extend in a variety of orientations, the present case discloses a number of improvements that are particularly well suited for use with top-hung, upwardly retractable, downwardly extensible, curtain-like closures that are formed from a tear-resistant fabric and that are used for such purposes as selectively closing side openings of freight carrying vehicles--closures that utilize the action of a power operated means and the influence of gravity to overcome the action of torsion spring members to cause the closures to extend by being "unrolled" in a downward direction, and that utilize the action of the torsion spring members to cause the closures to coil during upward retraction movement, with each curtain forming a separate roll when it is in its retracted position.
Stated in another way, whereas the Parent Case represented work of the three named inventors that took place during initial phases of a continuous and continuing program of research and development, the present application represents an improved work product that has emerged as the result of a continuing investment in this program--a work product that preferably incorporates novel and improved features that are particularly well suited for use in selectively closing vertically extending side wall openings of over-the-road freight hauling vehicles. Because much as been learned as retractable closures of the type disclosed in the referenced Parent Case have begun to be tested on over-the-road freight hauling vehicles, the present application addresses needs that have been discovered for improvement features, and discloses retractable closure improvement features that provide advantages that enhance and extend beyond the scope of the invention of the referenced Parent Case.